Purpose

This study examined how different course delivery formats influence outcomes of professional development (PD) related to teachers’ social–emotional competence (SEC), including teachers’ SEC, teaching self-efficacy, mental health status, and social and emotional learning (SEL) teaching beliefs. It also assessed whether teachers’ baseline levels moderated these effects.

Design/methodology/approach

The study used a nonequivalent pretest–posttest quasi-experimental design to evaluate BEST ME, a locally developed and empirically supported PD on SEC for teachers in Taiwan. While keeping the core content, learning objectives, and total training time (18 hours) constant, participants received one of two delivery formats: a half-day format (six weekly 3-hour sessions) or a full-day format (three 6-hour sessions every other week). Data were analyzed using one-way ANCOVA, and for variables violating the homogeneity-of-regression-slopes assumption, Johnson–Neyman procedures were used to assess conditional effects at different baseline levels.

Findings/results

The results revealed no significant differences between the two delivery formats in overall gains in SEC or SEL-related beliefs, suggesting that different delivery formats may yield comparable outcomes. However, in aspects related to teaching self-efficacy and mental health indicators such as depression, anxiety and stress, there were significant interaction effects between the program implementation structure and teachers’ initial states before the intervention. Specifically, teachers with higher teaching self-efficacy before the intervention showed greater improvement in the half-day training model, while those with lower self-efficacy before the intervention experienced greater progress in the full-day training model. Regarding mental health, teachers with higher levels of emotional distress before the intervention showed greater relief in the full-day training model, whereas teachers with lower levels of emotional distress before the intervention demonstrated greater improvements in depression, anxiety and stress indicators in the half-day training model.

Originality/value

This study broadens the existing research on teacher PD by showing that the effectiveness of interventions relies on both program content and various conditional factors. Building upon prior studies that mainly focused on average effects, the findings reveal that the success of PD in teachers’ SEC is influenced by several elements, such as curriculum content, how the program is implemented, and teachers’ initial conditions. This enhances our understanding of the factors contributing to the variability in teachers' professional growth.

Suggestions/implications

Overall, when promoting PD for teachers’ SEC, it is crucial to maintain the stability of core curriculum components while also considering how well the implementation methods match teachers’ characteristics. Educational authorities and schools should provide diverse, flexible options tailored to teachers’ initial conditions and practical needs to improve intervention effectiveness and ease of implementation. This study provides valuable empirical insights to inform future PD design and policy strategies aimed at strengthening teachers’ SEC.